CVE-2021-47865

Name: CVE-2021-47865
Creator: NVD / NIST
Published: 2026-01-21T18:16:18.47+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 0.54%

Last modified Jun 17, 2026

CVE-2021-47865 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. ProFTPD 1.3.7a contains a denial of service vulnerability that allows attackers to overwhelm the server by creating multiple simultaneous FTP connections. Attackers can repeatedly establish connections using threading to exhaust server connection limits and block legitimate user access.. EPSS estimates a 0.54% chance of exploitation in the next 30 days.

Description

ProFTPD 1.3.7a contains a denial of service vulnerability that allows attackers to overwhelm the server by creating multiple simultaneous FTP connections. Attackers can repeatedly establish connections using threading to exhaust server connection limits and block legitimate user access.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0

8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.54%

41.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-770

References

Timeline

Published: Jan 21, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2021-47865?

How severe is CVE-2021-47865?

CVE-2021-47865 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.54% probability of exploitation in the next 30 days.

How do I fix CVE-2021-47865?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-47865?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST